The present invention relates to an insert assembly and, more particularly, to an insert assembly for use in pre-stressed concrete structures, for example, pre-stressed concrete beams.
In the construction of certain buildings employing pre-stressed concrete beams, it has been found desirable to provide channel sections in the beams so that equipment such as piping, conduit, cable supports, shelving and the like may be secured or connected with the channel sections. One very well known type of channel section which may be used in the above fashion is sold commercially by Unistrut Corporation, Wayne, Mich., under the trade name "Unistrut" and includes a plurality of walls or sides arranged with respect to each other in a generally "U" configuration with edges of two of the walls opposing each other being inwardly turned to form flanges. These flanges define a longitudinal channel in the section with which connecting elements such as nuts, fittings, clamps and the like may be used for securing or connecting members with the channel section. A channel section such as described hereinabove is shown and described, by way of example, in U.S. Pat. Nos. 2,696,139 and 3,417,951, both of which are assigned to the same assignee as the present application.
In one method of construction of a concrete beam having a channel section therein as discussed hereinabove, the channel section is first placed within the formwork for the concrete beam and, after an elongated reinforcing member has been positioned adjacent to the channel section and placed under tension, a concrete mix is poured into the formwork and allowed to harden, following which the formwork is removed to produce the pre-stressed beam. A problem which has been observed in the abovedescribed operation is that it is difficult to firmly hold the channel section in place during the concrete pouring phase, especially since the concrete mix is generally agitated to eliminate the presence of air bubbles which could degrade the quality of the finished beam. Further, since the formwork is usually made of metal or some other permanent type of material, for rendering the formwork reusable, it is not desirable to bolt, nail or otherwise physically secure the channel section to the formwork.
The present invention is directed to an insert assembly which overcomes the problems as described hereinabove.